163 
with descriptions of new genera and species. 
cisely similar in every respect^ except in size, to that of the or- 
dinary frustule, would seem to indicate very slight, if any, differ- 
ence in the qualities of their respective endochromes. The spo- 
rangium — the product of this mixed endochrome — undergoes 
fissiparous division too in like manner with the ordinary frustules, 
and is thus converted into a number of sporangial frustides. In 
what way the small ordinary frustules are produced from these 
has not yet been observed. 
Why should not this conjugation of the endochrome in the 
lower plants be considered essentially the same process as what 
takes place during impregnation in the higher tribes ? The most 
eminent physiologists seem to be arriving at the opinion that the 
fertilization of the ovule, as it is termed, consists in the union of 
a part of the contents of a pollen-grain with certain matter con- 
tained in the ovule, and that the embryo originates from this 
mixed matter. The correctness of this opinion is rendered still 
more probable by the consideration of what takes place under 
the circumstances of hybridization of species. The phsenomena 
which present themselves in these cases are of 'the highest phy- 
siological interest, and it seems impossible after a careful consi- 
deration of them to doubt that the hybrid plant owes its ex- 
istence to — consists in its earliest condition of — an endochrome 
made up of a portion of the endochrome of each of the parent 
plants ; for the development of the hybrid embryo into the ma- 
ture plant indicates a quality of the contents of this embryonic 
cell of a character combining that of the endochrome of each of 
the two parents. A few facts will best illustrate the meaning of 
the foregoing observations. The ovules of Fuchsia coccinea fer- 
tilized with the pollen of Fuchsia fulgens produce plants of every 
intermediate form between these two species — some of the seed- 
ling plants closely resembling one, and others the other species, 
but the majority partaking equally of the characters of the two 
parents : scarcely however will any two be found so much alike 
as to be undistinguishable from each other. With respect to 
each of the hybrid seedlings separately considered, there is a uni- 
formity throughout in the mixed character of its various parts ; 
so that it is easy from the examination of the foliage to arrive at 
a tolerably correct idea of what will be the character of the 
blossom. Some persons perhaps will be disposed to believe that 
an endochrome may be modified in its character — that the pecu- 
liarities of the hybrid plant may be produced — by the situation 
in which it is at first developed ; but, if this were the fact, it is 
clear that the hybrid seedlings ought all to resemble each other 
as much as do individuals of one species, which is far from the 
truth, as has been just now stated. Moreover, a fact came under 
the observation of the writer which completely sets aside the 
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